A big purse with lots of compartments, each one with a zipper and big enough that one thing like a wallet doesn't get pulled out while digging out something else like an ID card. Each zipper is always opened and then closed again as I look in each compartment (it becomes a habit eventually).
I don't keep all important cards in one holder together, and the wallet with cash is separate with no ID in it. The wallet and several card holders are all bright colours or cutesie prints like kittens or flowers, not plain black that gets overlooked. The phone is bright yellow. I wear the purse on a long strap across the front of my body, not off one shoulder, and I never remove it until I get to where I'm going or home -- it stays in front of me, never to the side or back, like a mama kangaroo's pouch at all times except when sitting in a car with a seatbelt on. At home it lives in one place only, where it gets put as soon as I walk in the door.
I've twice left one credit card on a store counter while paying and signing for something, but both times the clerk saw it and put it away until I came rushing back. Otherwise I have my stuff pretty well trained not to play games with me and hide or run away from home. Except for reading glasses, which are the cheap drugstore-type that I buy in multiples so as to spread them around in many locations, but which still seem to have a herd mentality and migrate together into one place.